* 1939 – 1945, the Second Battle of the Atlantic.

Subsequent formalizations were framed as attempts to define " effective calculability " or " effective method "; those formalizations included the Gödel – Herbrand – Kleene recursive functions of 1930, 1934 and 1935, Alonzo Church's lambda calculus of 1936, Emil Post's " Formulation 1 " of 1936, and Alan Turing's Turing machines of 1936 – 7 and 1939.

* 1890 – Anthony Fokker, Dutch aviation engineer ( d. 1939 )

* 1939 – André Ouellet, French-Canadian politician

* 1852 – Ferdinand von Lindemann, German mathematician ( d. 1939 )

* 1939 – Alan Ayckbourn, English writer

* 1939 – Johnny Raper, Australian rugby league footballer

* 1939 – NBC inaugurates its regularly scheduled television service in New York City, broadcasting President Franklin D. Roosevelt's N. Y. World's Fair opening day ceremonial address.

* 1939 – First flight of the turbojet-powered Heinkel He 178, the world's first jet aircraft.

* 1939 – William Least Heat-Moon, American author

* 1939 – Edward Patten, American singer-songwriter and producer ( Gladys Knight & the Pips ) ( d. 2005 )

* 1939 – Bulle Ogier, French actress

* 1939 – Romano Prodi, Italian politician and statesman

* 1939 – Hércules Brito Ruas, Brazilian footballer

* 1939 – Albert Einstein and Leó Szilárd write a letter to Franklin D. Roosevelt, urging him to begin the Manhattan Project to develop a nuclear weapon.

* 1939 – Benjamin Barber, American theorist

* 1939 – Wes Craven, American director

* 1939 – John W. Snow, American politician, 73rd United States Secretary of the Treasury

* 1984 – Marvin Gaye, American singer ( The Moonglows ) ( b. 1939 )

* 2001 – Trinh Cong Son, Vietnamese composer ( b. 1939 )

Eastern European theorists include Pyotr Stolypin ( 1862 – 1911 ) and Alexander Chayanov ( 1888 – 1939 ) in Russia ; Adolph Wagner ( 1835 – 1917 ), and Karl Oldenberg in Germany, and Bolesław Limanowski ( 1835 – 1935 ) in Poland.

* Amateur film: Wathen collection: New York World's Fair, 1939-40 ( Part II ) ( 1939 ).

Due to the widespread purges of the Red Army officer corps in 1937 – 1939 " deep operations " briefly fell from favour, only later being gradually re-adopted following the embarrassment of the Red Army during the Winter War of 1939-40 when the Soviet Union tried to invade Finland.

Later that year on 22 October 1939 he made his first senior start when Cork played the newly-crowned All-Ireland champions Kilkenny in the opening round of the 1939-40 National Hurling League.

No official league was held during the Civil War between 1936 and 1939, until its resumption for the 1939-40 season and the first year back highlighted Betis decline as exactly five years after winning the title the club was relegated.

* 1939 New York World's Fair

His reputation grew in the USA following the critical reception of his design for the Finnish Pavilion at the 1939 New York World's Fair, described by Frank Lloyd Wright as a " work of genius ".

* 1939: Finnish Pavilion, at the 1939 New York World's Fair

Nin left Paris in the late summer of 1939, when residents from overseas were urged to leave France due to the upcoming war and returned to New York City with Guiler ( who was, on his own wish, all but edited out of her diaries published in her lifetime and whose role in her life is therefore difficult to gauge ).

New York City Guide: A Comprehensive Guide to the Five Boroughs of the Metropolis: Manhattan, Brooklyn, the Bronx, Queens, and Richmond ( 1939 ) online edition

Sagan recalls that one of his best experiences was when he was four or five years old, his parents took him to the 1939 New York World's Fair.

New York: H. W. Wilson, 1939.

Pare Lorentz's The Plow That Broke the Plains ( 1936 ) and The River ( 1938 ) and Willard Van Dyke's The City ( 1939 ) are notable New Deal productions, each presenting complex combinations of social and ecological awareness, government propaganda, and leftist viewpoints.

* 1939 – New York City's La Guardia Airport opens.

Soon after his arrival in New York City ( January 2, 1939 ), Fermi began working at Columbia University, where he had already given summer lectures in 1936 While at Columbia from 1939 – 42, until they moved to Chicago, Fermi and his wife resided in Leonia, New Jersey.

Doctrine and Action: Internal and Foreign Policy of the New Portugal, 1928 – 1939.

* 1939 – A Lockheed XP-38 flies from California to New York in 7 hours 2 minutes.

* 1939 – The erroneous word " dord " is discovered in the Webster's New International Dictionary, Second Edition, prompting an investigation.

1939 was a busy year, as he opened the 1939 New York World's Fair at Flushing Meadows-Corona Park, Queens, opened New York Municipal Airport No. 2 in Queens ( later renamed Fiorello H. LaGuardia Field ), and had the city buy out the Interborough Rapid Transit Company, thus completing the public takeover of the subway system.

Fluorescent lights were first available to the public at the 1939 New York World's Fair.

Futurama was an exhibit / ride at the 1939 New York World's Fair designed by Norman Bel Geddes that tried to show the world 20 years into the future ( 1959 – 1960 ).